The present application relates generally to a system and method for coordinating the operation of a transport vehicle and a harvester engaging in an “unload on the go” operation. The present application relates more specifically to a control system and method to control the trajectory of the transport vehicle relative to the harvester during an “unload on the go” operation.
Harvesters or harvesting machines pick up crop material, treat the crop material, e.g., remove any undesirable portions or residue, and discharge the crop material. Harvesters can discharge the crop material, either continuously as with a forage harvester or after intermediate storage as with a combine harvester, to a transport or transfer vehicle. The transport vehicle may be a tractor or truck pulling a cart, wagon, or trailer, or a truck or other vehicle capable of transporting harvested crop material. The harvested crop material is loaded into the transport vehicle via a crop discharging or unloading device, such as a spout or discharge auger, associated with the harvester.
During “unload on the go” operation of the harvester, the harvested crop material is transferred from the harvester to the transport vehicle while both vehicles are moving. The transport vehicle can travel next to and/or behind the harvester during unload on the go operation. Unload on the go operation is required for a forage harvester, since the forage harvester constantly discharges the harvested crop material. While unload on the go operation is not required for a combine harvester due to the combine harvester's intermediate storage capability, unload on the go operation is commonly used for a combine harvester to maximize the operating efficiency of the combine harvester.
To effectively implement unload on the go operation, the operation of the harvester and transport vehicle is coordinated to maintain the relative distance between the harvester and transport vehicle within an acceptable range. By maintaining the relative distance of the harvester and transport vehicle within an acceptable range, the position and orientation of the harvester unload spout and the position of the transport vehicle, specifically the portion of the transport vehicle receiving crop material, relative to the harvester unload spout position are maintained within an acceptable distance range to permit harvester unload on the go operation, i.e., the discharged crop material can be provided into the transport vehicle without loss to the ground. In other words, discharged crop material is directed to collect in the transport vehicle and is substantially prevented from being misdirected to miss the transport vehicle and collecting on the ground resulting in waste or loss of crop material. In order to maintain an acceptable distance range between the harvester and the transport vehicle, both the lateral (side to side) distance and longitudinal (fore and aft) distance between the harvester and transport vehicle have to be maintained within acceptable ranges.
Some control systems used for unload on the go operations can determine the position of the transport vehicle as a function of the harvester position plus one or more predetermined offsets. While this type of control system can be effective when the harvester travels in a straight line, unacceptable distance deviations may occur when the harvester changes position abruptly and the control system cannot adjust the position of the transport vehicle quickly enough to avoid crop material loss.
Therefore, what is needed is a system and method to control the trajectory of a transport vehicle during an unload on the go operation to prevent unacceptable distance deviations between the transport vehicle and the harvester.